Hi guys, I've got four SD315-88 Dayton subs which are doing quite well in about 4cf per driver tuned to 23Hz but my amp has no subsonic so I'm always a bit cautious and because I've got it tuned a bit low, my 50-80Hz bass is a bit weaker or has lost a bit of power handling.
So I am now thinking of doing something else. If I was to get four of these 15" drivers, can I expect the best of both worlds? Lets say 4-5cf sealed per driver? Extension down into the upper teens without worry of drivers unloading and also have good output elsewhere?
Dayton Audio DVC385-88 15" DVC Series Subwoofer 295-190
Specs look pretty good. Low FS and decent xmax. Q is a bit low for a sealed box but I dont know how much that will matter with four of them.
What do you guys think?
So I am now thinking of doing something else. If I was to get four of these 15" drivers, can I expect the best of both worlds? Lets say 4-5cf sealed per driver? Extension down into the upper teens without worry of drivers unloading and also have good output elsewhere?
Dayton Audio DVC385-88 15" DVC Series Subwoofer 295-190
Specs look pretty good. Low FS and decent xmax. Q is a bit low for a sealed box but I dont know how much that will matter with four of them.
What do you guys think?
It doesn't sound to me like you're current set-up is lacking in its ability to go loud, nor do you have a problem with deep bass extension. Tuning the drivers that low in such a large cabinet is giving you an extended bass shelf alignment, which does have a slowly decreasing output in the area you are saying is lacking. Usually this isn't an issue with subs because the frequencies are low and room gain usually compensates fairly well.
Before pulling out the wallet and throwing serious cash at the issue I would try optimising the current set-up.
The first issue you've got is with the potential for damaging the drivers at very low frequencies due to you lacking a sub sonic filter. How much power does the amplifier have that you are using to power them?
The other issue is with the lacking output in the 50Hz region.
Currently your response should look something like this.
And we can see why you might be experiencing the problems that you are. There is also the chance that room modes might be working against you.
The easiest way to fix the 50Hz issue is to increase the port tuning up to around 30Hz and this will give you something that looks like this.
It should help solve the one problem but due to the higher tuning frequency makes the problem of the driver unloading at sub sonics even worse.
The third option however is to introduce a high-pass. A simple 2nd order filter tuned to 28Hz with a Q of 1.26 will sort things out and you end up with something like this.
The high Q nature of the filter introduces a hump in the response that corrects for the loss around 50Hz, but it also protects the driver from any over excursion issues due to the driver loading at sub sonic frequencies. You can implement this either with a simple active filter built around an opamp, or you could build a PLLXO instead.
Now as you can also see from these sims, the driver isn't suited to reproducing bass down to 20Hz. If this is your goal then you will need to change to another driver, but first I would try correcting the problem with what you've already got.
Before pulling out the wallet and throwing serious cash at the issue I would try optimising the current set-up.
The first issue you've got is with the potential for damaging the drivers at very low frequencies due to you lacking a sub sonic filter. How much power does the amplifier have that you are using to power them?
The other issue is with the lacking output in the 50Hz region.
Currently your response should look something like this.
And we can see why you might be experiencing the problems that you are. There is also the chance that room modes might be working against you.
The easiest way to fix the 50Hz issue is to increase the port tuning up to around 30Hz and this will give you something that looks like this.
It should help solve the one problem but due to the higher tuning frequency makes the problem of the driver unloading at sub sonics even worse.
The third option however is to introduce a high-pass. A simple 2nd order filter tuned to 28Hz with a Q of 1.26 will sort things out and you end up with something like this.
The high Q nature of the filter introduces a hump in the response that corrects for the loss around 50Hz, but it also protects the driver from any over excursion issues due to the driver loading at sub sonic frequencies. You can implement this either with a simple active filter built around an opamp, or you could build a PLLXO instead.
Now as you can also see from these sims, the driver isn't suited to reproducing bass down to 20Hz. If this is your goal then you will need to change to another driver, but first I would try correcting the problem with what you've already got.
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Hi 5th Element. Thanks for the help! It just goes to show that there is so much I have to learn! Well as I was reading and looking at your graphs, it dawned on me that there was something I read about long ago that I thought I did which I didnt do and that was to bypass the external crossover that was feeding my power amp (a vintage souncraftsmen PM860 which is 200wrms per channel at 8 ohms). I just tried it. Bypassed the crossover and going directly from the LFE output of the Denon receiver to the inputs of the amp. It made a huge change in my middle bass area. Wondering why (because my crossover should have been set to 90Hz anyway which is higher than my receivers 80Hz LFE), I opened it up and looked at the resistor pack that was in it - yes the crossover is so old that you set the crossover point with resistors. LOL. Anyway I had made a mistake. The crossover pack worked out to like 55Hz so no wonder I was lacking a lot of bass. BTW the crossover I'm using is an old audiocontrol phase coupled activator.
So now things have improved quite a bit as far as balance, I just have to figure out a way of having the extreme lows filtered out. I did find this product page that claims to have crossover filters that work with line level. They say they have a 20Hz subsonic filter.
Crossovers
Maybe I should give that a shot. Doesnt seem so expensive if it works....
So now things have improved quite a bit as far as balance, I just have to figure out a way of having the extreme lows filtered out. I did find this product page that claims to have crossover filters that work with line level. They say they have a 20Hz subsonic filter.
Crossovers
Maybe I should give that a shot. Doesnt seem so expensive if it works....
5th element, I think I have found the subs for me! I will replace the four 12" with two of these Dayton DVC385-88 15". They have more than twice the xmax and seem to have awesome extension. Best of all each 15 fits quite nicely in the airspace of my two 12" (which I have two drivers in 8cf boxes). All I need to do is glue and cut a new baffle to the existing boxes and away I go! Oh I'd change the tuning to 17 or 18Hz.
Dayton Audio DVC385-88 15" DVC Series Subwoofer 295-190
Dayton Audio DVC385-88 15" DVC Series Subwoofer 295-190
Ah so you're saying that even though the Denons LFE output was set to 80Hz your other crossover was set to 55Hz instead of 90 and as a result you were missing bass as the subs were cutting out too soon. It's good that you found this out now rather then later!
Those crossover things are more then likely just a PLLXO inside a pretty case. Here is a link to a website that details roughly what they are about. It'd be far cheaper to make one yourself and then you'd also have the option to tailor the filter to your power amplifiers input impedance.
Those crossover things are more then likely just a PLLXO inside a pretty case. Here is a link to a website that details roughly what they are about. It'd be far cheaper to make one yourself and then you'd also have the option to tailor the filter to your power amplifiers input impedance.
Oh very cool link you just sent me. I definitely dont care about the pretty case if I can make my own! ... and ya about my crossover. I mistakenly chose the wrong resistor values which shifted the crossover to 55Hz at 18db/oct. I'm very happy and I would have never bothered doing any of this if you didnt respond and make me re-think my setup.
PS. I still want those 15" 🙂 ... the ones in my link. Looks like two of them would be awesome bass. I can then sell my SD315's cheap to people at work or what not.....
PS. I still want those 15" 🙂 ... the ones in my link. Looks like two of them would be awesome bass. I can then sell my SD315's cheap to people at work or what not.....
If you really want to throw some money at the situation then I'd recommend you go for a proper upgrade. Daytons own reference series of subs
Dayton Audio RSS390HF-4 15" Reference HF Subwoofer 4 Ohm 295-468
For example is a little bit more expensive then what you've linked but I don't think you'd be disappointed. Many people have built subs using these drivers and are extremely happy with them.
In an 8 cu ft enclosure, 30% fill and tuned to 16Hz, you get a response that looks something like this.
Given your amplifiers output voltage capabilities, the low tuning frequency also gives control over the drivers excursion down to around 12Hz. That's if you wire them in series, which I am assuming you would.
I'd still recommend a sub sonic filter at 10Hz or so though just to be safe.
Of course the driver you linked to would most likely do similar things, but if this were my money I'd go for the driver I linked as they have more advanced motors and occupy a pretty nice place as far as value for money goes, after which you end up very much in the realm of diminishing returns.
Within the capabilities of your amplifier, a pair of those will give you THX level bass reproduction down to 20Hz in room and with plenty of Xmax to spare.
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Ya those are very nice as well. Hmmm. Its a price difference of about $100 in the grand scheme of things. I guess not much. They do model similarly. Hmmm will have to think. BTW this is the amp in question. Its a stereo amp which is 200wpc at 8ohms, 300 at 4ohms and approx 400wpc at 2ohms stereo but even though it was rated for that, its built in fan would ramp up to high and become annoying so 8 and 4 is what I'd consider as possible loads.... plus I've always noticed not loading an amp down seems to give me more control and tighter bass response for only a tiny drop in volume.
An externally hosted image should be here but it was not working when we last tested it.
If you really want to throw some money at the situation then I'd recommend you go for a proper upgrade. Daytons own reference series of subs
Dayton Audio RSS390HF-4 15" Reference HF Subwoofer 4 Ohm 295-468
For example is a little bit more expensive then what you've linked but I don't think you'd be disappointed. Many people have built subs using these drivers and are extremely happy with them.
In an 8 cu ft enclosure, 30% fill and tuned to 16Hz, you get a response that looks something like this.
Given your amplifiers output voltage capabilities, the low tuning frequency also gives control over the drivers excursion down to around 12Hz. That's if you wire them in series, which I am assuming you would.
I'd still recommend a sub sonic filter at 10Hz or so though just to be safe.
Of course the driver you linked to would most likely do similar things, but if this were my money I'd go for the driver I linked as they have more advanced motors and occupy a pretty nice place as far as value for money goes, after which you end up very much in the realm of diminishing returns.
Within the capabilities of your amplifier, a pair of those will give you THX level bass reproduction down to 20Hz in room and with plenty of Xmax to spare.
Tino - I would strongly suggest going with a 2x4 minidsp in your setup prior to changing around your subs. Even if you are not using it as the main crossover, it will give programmable PEQ and high/low pass filters that will let you dial in the setup. You could even do 4 channel individual filtering and time correction of each woofer.
http://www.minidsp.com/products/minidsp-in-a-box
http://www.minidsp.com/products/minidsp-in-a-box
turbodawg, that does seem very interesting! I may just be ordering one of these to play with regardless of what happens 🙂
As someone who uses DSP too I can only support turbodawg's recommendation. The miniDSP are very cost effective and would be a very good starting point for perhaps ending up with a multiple sub set-up.
Well you know what, I've gone ahead and purchased the subwoofers (two 15 DVC385) ... umm and the DSP 🙂
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Okay so i just got a new car and some of the trunk dimensions are 36"w x 28"d x 18"h.
could this thing be folded to fit in that space?
could this thing be folded to fit in that space?
Hi,
No, Simple DIY calculations: Your mentioned internal volume using 0.75” wood is only ~247L.
You need at least 304L internal volume for a dual driver box, but a single driver requires ~171L = ~6 cu.ft, IMO good for home HT-use.
If built and installed in a car: Problem that may occur is exaggerated FR at the low end if not tailored with a suitable HPF.
I would instead consider a ~80 L closed box that would have a f-3dB at ~41Hz for a single driver.
b 🙂
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